Add basic ExtensionPoint support.

Shared/ExtensionPoints/SendToMicroBlogCommand.swift

@@ -0,0 +1,97 @@
+//
+//  SendToMicroBlogCommand.swift
+//  NetNewsWire
+//
+//  Created by Brent Simmons on 1/8/18.
+//  Copyright © 2018 Ranchero Software. All rights reserved.
+//
+
+import AppKit
+import Articles
+import RSCore
+
+// Not undoable.
+
+final class SendToMicroBlogCommand: ExtensionPoint, SendToCommand {
+
+	let title = NSLocalizedString("Micro.blog", comment: "Micro.blog")
+	let templateImage = AppAssets.extensionPointMicroblog
+
+	var image: NSImage? {
+		return microBlogApp.icon
+	}
+
+	private let microBlogApp = UserApp(bundleID: "blog.micro.mac")
+
+	func canSendObject(_ object: Any?, selectedText: String?) -> Bool {
+
+		microBlogApp.updateStatus()
+		guard microBlogApp.existsOnDisk, let article = (object as? ArticlePasteboardWriter)?.article, let _ = article.preferredLink else {
+			return false
+		}
+
+		return true
+	}
+	
+	func sendObject(_ object: Any?, selectedText: String?) {
+
+		guard canSendObject(object, selectedText: selectedText) else {
+			return
+		}
+		guard let article = (object as? ArticlePasteboardWriter)?.article else {
+			return
+		}
+		guard microBlogApp.launchIfNeeded(), microBlogApp.bringToFront() else {
+			return
+		}
+
+		// TODO: get text from contentHTML or contentText if no title and no selectedText.
+		// TODO: consider selectedText.
+
+		let s = article.attributionString + article.linkString
+
+		let urlQueryDictionary = ["text": s]
+		guard let urlQueryString = urlQueryDictionary.urlQueryString else {
+			return
+		}
+		guard let url = URL(string: "microblog://post?" + urlQueryString) else {
+			return
+		}
+
+		let _ = try? NSWorkspace.shared.open(url, options: [], configuration: [:])
+	}
+}
+
+private extension Article {
+
+	var attributionString: String {
+
+		// Feed name, or feed name + author name (if author is specified per-article).
+		// Includes trailing space.
+
+		if let feedName = webFeed?.nameForDisplay, let authorName = authors?.first?.name {
+			return feedName + ", " + authorName + ": "
+		}
+		if let feedName = webFeed?.nameForDisplay {
+			return feedName + ": "
+		}
+		return ""
+	}
+
+	var linkString: String {
+
+		// Title + link or just title (if no link) or just link if no title
+
+		if let title = title, let link = preferredLink {
+			return "[" + title + "](" + link + ")"
+		}
+		if let preferredLink = preferredLink {
+			return preferredLink
+		}
+		if let title = title {
+			return title
+		}
+		return ""
+	}
+
+}